The present embodiments relate to a control device for controlling an irradiation procedure in a particle therapy unit, a particle therapy unit, and a method for irradiating a target volume.
Particle therapy is used for the treatment of tissue, such as tumor diseases. Irradiation methods used in particle therapy may, however, also be used in non-therapeutic fields. The non-therapeutic fields include, for example, research work in the context of particle therapy, carried out on non-living phantoms or bodies, or irradiation of materials. In such methods, charged particles are accelerated to high energies, formed into a particle beam and directed onto an object that is to be irradiated. The particle beam penetrates the object and releases its energy in a defined location, which leads to the destruction of the tissue in the defined location. The particles used are protons and carbon ions, but pions, helium ions and other types of ions are also used.
Compared to irradiation methods using x-ray beams, particle therapy has the distinguishing feature that the particles in the particle beam release the main part of their energy in an area that can be relatively well defined within the target volume. Exactly where the particle beam interacts with the target volume, for example, at what depth of the target volume in terms of the direction of the beam, depends mainly on the energy of the particle beam. The higher the energy of the particle beam, the further the particle beam penetrates into the target volume and the deeper is the area in which the particles discharge their energy onto the target volume. Accordingly, a target volume that is to be irradiated within an object may be irradiated with relative precision. Irradiation in surrounding areas may be avoided.
A target volume may be irradiated in a plurality of layers. The target volume is irradiated in a plurality of layers when the target volume in the direction of the beam is so large that the layer in which particles release their energy with a defined energy is so thin that the target volume cannot be captured by the particle beam by particles with the defined energy. Irradiation of the target volume often ensues in layers, the energy of the particles being adjusted in each layer to the depth of the layer in the object that is to be irradiated.
The energy of the particles is adjusted immediately in front of the object that is to be irradiated, and before the irradiation procedure, for example, in the area of the accelerator. The particles are accelerated to an energy that is required for irradiation, or in the area of the high-energy beam transport system with which particles are transported from an accelerator to an irradiation chamber.
Complex irradiation procedures, such as irradiating a plurality of layers, require complex control of the particle therapy unit and synchronization of the energy of the particle beam with the layers that are to be irradiated.